• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.163-163
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• 2011

평활입자동역학법(SPH, Smoothed Particle Hydrodynamics)은 붕괴파(도수, 댐붕괴류, 쇄파) 등과 같이 수면 변동이 큰 유체 역학 문제를 해결하기 위한 무격자법 중의 하나이다. SPH를 이용한 붕괴파의 모의에서는 압력, 점성, 밀도(압축성), 척력 등 다양한 계산 인자가 필요하다. 이들 인자가 SPH 모의 결과에 미치는 영향을 도수와 댐붕괴류에 대해서 검토하였다. 그 결과 압력과 관련하여, 상태 방정식 계수로 표현되는 유체의 음속은 입자들의 흩어짐 현상과 밀접한 관계를 가지는 것을 밝혀내었다. 평활 거리는 수치해의 안정성과 밀접한 관련이 있으며, 너무 작거나 크게 설정하는 경우 해의 정확도가 떨어지는 것으로 나타났다. 일반적으로 2차원 문제의 경우 20~23개 정도의 입자가 해의 내삽에 사용되는 것이 바람직하다.

• 중국학논총
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• no.69
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• pp.53-74
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• 2021

本文考察了'都-數量詞'构式的分布特点和語用特征。首先, '都-數量詞'构式的分布可以分爲'都'出現在數量詞前, '都'和數量詞之間有動詞出現, '都'的前或后有副詞出現等三种情况。在這三种'都-數量詞'句子中'都'表示一种情態意義, 指一个主觀大量; 超過听話人或設話人所預設的數量或程度。其次, '都-數量詞'构式的語用特征可以簡单概括爲以下兩点。第一, '設話人所要表達的尺度的含蓄性'; 數量詞在句子中表示一定的尺度, 在這个尺度范圍里它會指可能性最低值, 所以'都'在构式中表示設話人所要表達的尺度的含蓄性。第二, '焦点敏感算子'; 從信息結构的觀点考察'都-數量詞'句子, 發現有自然焦点結构和句子焦点結构等兩种類型, 其中'都'在句子中有焦点敏感算子的功能。

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.611-619
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• 2017

This paper intends to develop unit water production cost (UWPC) between alternative water resources including desalination, freshwater reservoirs, single-purpose dams, underground dams, and two indirect water in-take technologies - riverbank filtration and aquifer storage and recovery (ASR). The UWPCs of water supply schemes including each alternative are determined based on project cost, and operation and maintenance estimation models, which were developed based on real project cost data. The sensitivity analysis of UWPCs reveals that ASR is the lowest cost option in producing drinkable water among the alternatives, followed by riverbank filtration and underground dam. It is expected that economics related to the finding plays a critical role in supporting water resources planning and budget allocation for central and local water authority in Korea.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.77-82
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• 2008

This paper presents a Reliability-Based Topology Optimization(RBTO) using the Evolutionary Structural Optimization(ESO). An actual design involves some uncertain conditions such as material property, operational load and dimensional variation. The Deterministic Topology Optimization(DTO) is obtained without considering the uncertainties related to the uncertainty parameters. However, the RBTO can consider the uncertainty variables because it has the probabilistic constraints. In order to determine whether the probabilistic constraints are satisfied or not, simulation techniques and approximation methods are developed. In this paper, the reliability index approach(RIA) is adopted to evaluate the probabilistic constraints. In order to apply the ESO method to the RBTO, sensitivity number is defined as the change in the reliability index due to the removal of the ith element. Numerical examples are presented to compare the DTO with the RBTO.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.529-538
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• 2010

This paper presents a reliability-based topology optimization (RBTO) based on bidirectional evolutionary structural optimization (BESO). In design of a structure, uncertain conditions such as material property, operational load and dimensional variation should be considered. Deterministic topology optimization (DTO) is performed without considering the uncertainties related to the design variables. However, the RBTO can consider the uncertainty variables because it can deal with the probabilistic constraints. The reliability index approach (RIA) and the performance measure approach (PMA) are adopted to evaluate the probabilistic constraints in this study. In order to apply the BESO to the RBTO, sensitivity number for each element is defined as the change in the reliability index of the structure due to removal of each element. Smoothing scheme is also used to eliminate checkerboard patterns in topology optimization. The limit state indicates the margin of safety between the resistance (constraints) and the load of structures. The limit State function expresses to evaluate reliability index from finite element analysis. Numerical examples are presented to compare each optimal topology obtained from RBTO and DTO each other. It is verified that the RBTO based on BESO can be effectively performed from the results.

• Journal of Korea Water Resources Association
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• v.50 no.3
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• pp.201-210
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• 2017

This study proposes a numerical model which is able to simulate turbidity currents intruding into a reservoir and resulting sediment depositions. The proposed model is applied to laboratory experiments by Toniolo and Schultz (2005), and propagation of turbidity currents, morphological change, and trap of suspended sediment are simulated. It is simulated that the turbidity current after plunging at the foreset of the model delta, propagates along the bottom. The thickness of the turbidity current increases significantly after being blocked by the dam, and this effect is propagated in the upstream direction. In addition, it is simulated that the foreset moves in the downstream direction due to both the bedload and suspended load and the thickness of the bottom set increases due to the suspended load. It is found that the height of the intake affects the thickness of the turbidity current and the location of the internal hydraulic jump. The impact of the height of the intake on the trap efficiency is not clear in the experimental results, however, overall trap efficiency is predicted quite successfully by the model. Also, sensitivity analysis is carried out, and the results indicates that the particle size affects the trap efficiency most.

• Journal of the Korean Regional Science Association
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• v.32 no.1
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• pp.3-26
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• 2016

This study aims to examine the influence of the Daegu Subway Line 3 construction on apartment price fluctuation and to find the factors causing the apartment price fluctuation in the station area of the Daegu Subway Line 3. Empirical results of this study are as follows: first, the apartment price is more fluctuated or increased at the time of completion of subway construction than at the time of breaking ground; second, the opening of the Daegu Subway Line 3 has positive impact on apartment price nearby the station area of the Daegu Subway Line 3, especially apartment prices in the second station area (200-600m) are positively related to the opening of the Daegu Subway Line 3; third, medium-large size ($85-135m^2$) and large size (excess of $135m^2$) apartment are sensitively related to the apartment price fluctuation by the Daegu Subway Line 3 construction; and fourth, Buk-gu and Suseong-gu areas are the main beneficiaries. The results of this study suggest implications for tax and redistribution policies in the station areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1126-1139
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• 2014

World is experiencing abnormal weather caused by urbanization and industrialization increasing greenhouse gas and one of these phenomenon domestically happening is flood and drought. The increase of green-house gases is due to urbanization and industrialization acceleration which are causing abnormal climate changes such as the El Nino and a La Nina phenomenon. It is expected that there will be many difficulties in water management, especially considering the topography and seasonal circumstances in Korea. Unlike in the past, a variety of water conservation initiatives have been undertaken like the river-management flow and water capacity expansion projects. To meet the increasing demand for water resources, new environmentally-friendly small and medium-sized dams have been built. Therefore, the development of a new paradigm for water resources management is essential. This study shows that additional security is needed for potential water resources through diversion tunnels and is very important to consider for future water supplies and situations. Using RCP 6.0 and RCP 8.5 in representative concentration pathway climate change scenario, specific hydrologic data of study basin was produced to analyze past observed basin rainfall tendency which showed both scenario 5%~9% range increase in rainfall. Through sensitivity analysis using objective function, population in highest goodness was 1000 and cross rate was 80%. In conclusion, it is expected that the results from this study will help to make long-term and stable water supply plans by using the potential water resource evaluation model which was applied in this study.